Torres Quiñones, Jorge
(2024)
Exploring the Surface Interactions of Graphene for Applications in Dual-Sided Field Effect Transistors.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Graphene is a two-dimensional (2D) material with superior electrical properties that make it attractive for electronic applications. These applications often desire higher transistor densities, leading to the formulation of a dual-sided wafer. Its large surface area to volume ratio renders it extremely susceptible to surface effects, necessitating increased understanding to develop higher quality devices. Large-scale incorporation of graphene requires a growth and transfer process that can affect its properties. It is essential to understand how graphene may be transferred cleanly for improved reliability and CMOS compatibility. Additionally, strong adhesion is desired to withstand the stresses a device can undergo during fabrication and operation. How graphene’s electrical conduction is modulated by different substrates is crucial to improving the design and reliability of graphene-based devices. Recent advances in graphene transfer and how these improvements can be incorporated will be discussed. Easy to implement solutions include ammonium persulfate etching of copper foil, heated acetic acid, and lower molecular weight PMMA. The adhesion energy of graphene to SiO2, Si3N4, gold, and platinum substrates was investigated using the intercalation of nanoparticles method. A key aspect of the adhesion energy was how polarizable the interface material was, with increasing polarization bringing larger adhesion energies. Gold was found to have the largest adhesion energy at 7687.10 mJ m-2. Interfacial effects on the electrical conduction of single layer graphene (SLG) and multilayer graphene (MLG) were investigated by determining the temperature coefficient of resistance (TCR). The strongest effect without surface modifications was for SLG on Si3N4, where the sheet resistance changed 0.393%/K. The modifications strongly affected graphene’s properties and offered avenues for improvement, showing a 0.456% change for SLG on SiO2. The results of these experiments were used to develop a dual-sided graphene field effect transistor (GFET). GFETs were developed on both sides of the wafer, with electron and hole mobilities measured up to 1259 and 512 cm2 V-1 s-1. The fabrication of these transistors allows for new device architectures to create compact and versatile devices. The devices are CMOS compatible and can offer higher transistor densities than previously possible.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
6 September 2024 |
| Date Type: |
Publication |
| Defense Date: |
4 June 2024 |
| Approval Date: |
6 September 2024 |
| Submission Date: |
30 May 2024 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
133 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Electrical and Computer Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
graphene, transfer, adhesion, TCR, dual side |
| Date Deposited: |
06 Sep 2024 19:54 |
| Last Modified: |
06 Sep 2024 19:54 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/46446 |
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